Vane type pump



Oct. 20, 1964 J. B. CASTLE, JR.. ETAL 4 VANE TYPE PUMP 7 Filed June 12, 1961 6 Sheets- Sheet 1 INVENTORS JAMES B. CASTLE,JR. EUGENE W. PEARSON BYROLLAND A- RlCHARDSON M wM THE/l"? ATTORNEYS VANE TYPE PUMP Filed June 12, 1961 6 Sheets-Sheet 2 INVENTORS JAMES B. CASTLE JR.

EUGENE w.PEARs6N BY ROLLAND A.RI( 3HARDSON M Y M THE/R ATTORNEYS Oct. 20, 1964 VANE TYPE PUMP Filed June 12, 1961 J. B. CASTLE, JR., ETAL 6 Shets-Sheet s INVENTORY JAMES B. CASTLE,JR. EUGENE W. PEARSON BYROLLAND A.RICHARD$ON THE/R ATTORNEYS Oct. 20, 1964 J. B. CASTLE, JR.. ETAL 3,153,334

Oct. 20, 1964 J. B. CASTLE, JR, ETAL 3,1 3,384

VANE TYPE PUMP Filed June 12, 1961 s Sheets-Sheet 5 Fig.7.

INVENTORS JAMES B. GASTLE,JR. EUGENE W. PEARSON BY ROLLAND A.RIOHARDSON JR.. ETAL 3,153,384

Oct. 20, 1964 INVENTORS JAMES B. OASTLE,JR.

NE W. PEARSON EU BYROLLAND A.RIOHARDSON M 9 73M THE/I? ATTORNEYS J United States Patent 3,153,384 VANE TYPE PUMP James B. Castle, In, 221 Park Way, Piedmont, Calif., and

Eugene W. Pearson, Orinda, and Rolland A. Richardson, Alameda, Califi; said Pearson and said Richardson assignors to Pacific Industrial Manufacturing (10., Alameda, Califl, a corporation of California Filed June 12, 1961, Ser. No. 116,396 3 Claims. (Cl. 103-120) Our invention relates to pumps and more particularly to a pump of the vane type.

Among the objects of our invention are:

(1) To provide a novel and improved vane type pump;

(2) To provide a novel and improved vane pump of the type whose capacity may be varied;

(3) To provide a novel and improved vane pump whose capacity is not only adjustable, but one capable of reversing the flow of liquid therethrough;

(4) To provide a novel and improved vane type pump wherein frictional losses are minimized to the extent of substantially increasing the efficiency of the pump;

(5) To provide a novel and improved vane type pump capable of operating at high speed and pressure;

(6) To provide a novel and improved vane type pump in which the vanes are continually pressured radially at pump pressure, against a rotor peripheral bearing assembly to minimize losses and permit increase of pump pressure and operating speed;

(7) To provide a novel and improved twin pump of the vane type;

(8) To provide a novel and improved twin pump of the vane type, with both sections functioning simultaneously and each section capable of fulfilling all the preceding objects;

(9) To provide a novel and improved reversible variable displacement pump of the vane type; and

(10) To provide a novel and improved twin pump of the vane type with each section capable of functioning as a reversible variable displacement pump.

Additional objects of our invention Will be brought out in the following description of a preferred embodiment of the same, taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a view in section through a pump of the present invention in the form of a twin pump;

FIG. 2 is a view in section taken in the plane 2-2 of FIG. 1;

FIG. 3 is a view in section taken in the plane 3-3 of FIG. 1;

FIG. 4 is a view in section taken in the plane 4-4 of FIG. 1;

FIG. 5 is an end view of a porting rotor component of the pump of FIG. 1;

FIG. 6 is a fragmentary view of a valve detail depicted in phantom in FIG. 3;

FIG. 7 is a fragmentary view in cross section of a modification of the pump assembly of FIG. 1;

FIG. 8 is a view through the embodiment of FIG. 7, taken in a plane corresponding to that of FIG. 2, but without the pump housing; and

FIG. 9 is a view in section through the embodiment of FIG. 7, taken in a plane corresponding to that of FIG. 4.

Referring to the drawings for details of our invention as illustrated therein, the same comprises a substantially ice cylindrical pump housing 1 with a lateral enlargement 3, the housing having outer side walls 5 and 7, and a common partition wall 9, to provide twin housing chambers 11, 13. The walls of the housing chambers define concentric wall openings with centers on a common axis.

Within each housing chamber is a pivot ring 15 of smaller outside diameter than the inner diameter of its housing chamber, to permit adjustable movement of the ring within such chamber. For such purpose, the ring is formed with a tapered peripheral boss 17 adapted to freely extend into the interior of the enlargement 3 of the housing chamber, the chamber walls and peripheral boss having aligned openings to receive a pivot pin 19 whereby to permit pivotal movement of each pivot ring within its housing chamber.

At a location diametrically opposite the pivot pin, each pivot ring is provided with a stem 21 preferably terminating in a knob and extending into a common opening provided through the housing, said opening spanning both chambers and being framed by heavy flange 23. With each pivot ring so mounted, it is adapted to swing through a neutral position of coinciding diameters or 00- inciding centers of the ring and housing.

Each pivot ring, by its cylindrical internal wall, defines, in part, a pump chamber for a pump rotor assembly 31 which is fixedly mounted on a shaft 33 passing axially of the housing chambers, the rotor assemblies being separated from each other by a shaft mounted spacer 35.

Each such rotor assembly involves a disk or narrow cylinder 37 having an axial shaft passage and a key 39 for keying the cylinder onto the shaft.

Included in each rotor cylinder, are a plurality of substantially radial vane slots 41 and intake-discharge flow channels 43, both terminating in the periphery of the rotor cylinder 37 with the intake-discharge flow channels between the vane slots.

A vane 47 is slidably positioned in each of the vane slots, the vanes at their outermost edges being adapted to engage slidable bearing means 51 encircling the outer edges of the vanes within the pump chamber defined by the associated pivot ring.

Such slidable bearing means may take different forms, but in the preferred form of the invention, the same includes an outer race 53 snugly fitting within the pump chamber defining surface of the pivot ring 15, an inner race 55 about the outermost edge of the vanes and engageable by the vanes, and a plurality of anti-friction bearing elements 59 between and in rolling contact with these races.

Flow to and from each rotor is provided for by a porting rot-or 61 which is a component of generally cylindrical form having an axial bore therethrough and provided with a key way for keying this component onto the pump shaft 33, with one end of the component engaging the proximate pump rotor.

Longitudinally through the porting rotor are a plurality of flow passages 63 corresponding in number to the number of intake-discharge channels 43 in the rotor cylinder 37, each passage flow connecting with one of such intake-discharge passages. 7

When so keyed to the pump shaft, the porting rotor 61 will rotate with the pump rotor assembly 31 while maintaining intact, the flow connection between each of the porting rotor passages 63 and its associated rotor intakedischarge channel 43.

To permit free rotation of the porting rotor, with respect to adjacent or proximate stationary components of the pump assembly, it is journalled in a bearing assembly 69 involving an inner race 79, the function of which may be taken over by the outer surface 71 of the porting rotor if desired; an outer surrounding race 73 and intermediate rotor bearing elements 75.

The outer race 73 is supported within an overhanging lateral extension 79 of an end housing 81, which extension is provided with a laterally extending flange 83 to snugly fit Within the proximate side opening of the pump,

housing 1, with the end surface of the lateral extension of the end housing in abutment against the proximate side Wall of the pump housing. When so fitted, each end housing 81 may be bolted to the pump housing 1 by a plurality of bolts 87 passing through the end housing and threading into the side walls of the pump housing. By chamfering the enclosed edge of the pump housing and assembling an O-ring seal 91 under compression within the space thus provided, the joint between the pump housing and end housing may be sealed against leakage from within.

Each end housing has an axial opening approximating the outside diameter of the adjacent end of the porting rotor, and at diametrically opposite locations, is provided an intake-discharge port 95 extending radially therethrough and fanning out as a groove 97 about the internal circumference of the end housing for a distance short of meeting the corresponding inner end groove of the opposite intake-discharge port. Each of these ports may function either as an intake or discharge port while the other functions in the opposite sense, depending upon the prevailing adjusted position of the pivot ring with respect to its neutral position.

To complete a flow connection between each of the intake-discharge ports 95 and the associated pump rotor assembly 31 by way of the intervening porting rotor 61, a port plate 101 is provided for assembly within the axial opening of the end housing. This port plate has an axial opening of greater diameter than the pump shaft, and is formed with upper and lower arcuate recesses 103 in the opposing sides thereof, such arcuate recesses spanning an angle corresponding substantially to that covered by the angular'spread of each of the intake-discharge ports at its inner end. The opposing recesses are inter-connected, preferably by a plurality of holes 105 with each of said holes exposed at the periphery of the port plate by a radial passage 107.

The port plate is symmetrically retained in its assembled position within the end housing by a single key 109 positioned within aligned key Ways provided in both the port plate and the end housing. Such key prevents relative rotation of the port plate within its end housing, while Permitting substantially free floating adjustment of the port plate in the axial direction.

Such floating adjustment is further made possible by the introduction of a spacer 111 on the motor shaft 33 within the axial passage of the port plate, the spacer having a length slightly greater than the corresponding dimension of the port plate and is clamped between the adjacent porting rotor 61 and a balance plate 115 positioned on the shaft within the proximate end housing 81.

The balance plate 115 atthe drive motor end of the pump shaft, is retained by a shoulder 117 on the shaft, while at the remote end of the shaft, the associated balance plate is retained by a washer 121, the entire pump rotating portion of the pump assembly being maintained under heavy clamping pressure by a nut 123 threaded onto the remote end of the shaft in engagement with this washer.

A motor bracket 125 bolted to the end housing at the motor end of the pump assembly, is adapted to support a drive motor 127, and at the same time provides for the installation of a shaft seal 129 and a seal 131 between the pump bracket and the proximateend housing, both i seals functioning to preclude leakage from that end of the pump assembly.

At the remote end of the pump assembly, an end cap 135 engaging the proximate end housing and providing an enclosure for the clamping nut 123, is bolted to the aforementioned end housing by end bolts 137. An O-ring seal 139 between the end housing 81 and the end cap 135 will respond to pressures within the end cap to seal off the joint between the end cap and the proximate end housing, to prevent leakage at this end of the pump assembly.

With a motor keyed to the shaft and energized, all pump assembly components keyed to the shaft or otherwise clamped between the shoulder 117 adjacent the motor end of the shaft and the clamping nut 123 on the remote end, will rotate with the shaft. These components will include the pump rotor assemblies 31 and intervening spacer 35, the porting rotors 61, the end spacers 111, and balance plates 115. With each of the pivot rings 15 shifted to its mid or neutral position, that is, with its center coinciding with the center of the included rotor assembly, a condition of symmetry prevails, and all rotor chambers defined by the rotor vanes 47 in their extended positions, will be of the same capacity. Consequently, a condition of hydraulic balance will exist with respect to the associated intake-discharge ports of the pump assembly. Under these conditions, no pumping will occur.

However, upon shifting the pivot ring to a position olfcenter with respect to the axis of the rotor, the rotor vanes may extend outwardly to a greater degree on one side of the rotor cylinder periphery and to a less extent on the diametrically opposite side. As the rotor rotates, such extended vanes will be forced inwardly to reduce the capacity of the chamber formed by such vanes while those previously occupying a position closer to the center of the rotor cylinder, will acquire room to move outwardly to enlarge the chambers between them. Under these conditions, as the rotor rotates, a condition of subatmosphere pressure will be developed in the peripheral chambers of the rotor assembly as the chambers expand in volume, and as the same chambers later begin to decrease in volume, that is when the vanes are forced inwardly of the rotor cylinder, the pressure upon the liquid in the chamber increases, such liquid being gradually exposed to those porting rotor passages in connection therewith and will discharge through such passages to the associated intake-discharge port, under which circumstances, that particular port becomes the discharge port for that section of the pump assembly, While the diametrically opposite intake-discharge port will become the intake or suction end of that portion of the pump assembly.

By shifting the pivoted ring from the aforementioned discussed position through its neutral position to a position on the other side of the axis of the rotor, the conditions will become reversed, and that port which previously functioned as the discharge port, will now become the intake or suction end of that section of the pump assembly, while the remaining port will become the discharge port.

The pressures at which the pump assembly will discharge, will vary with the degree to which the pivotedv ring is adjusted beyond its neutral position, while of course, the direction of flow through the pump will dependupon which side the neutral position the pivot ring has been shifted.

Inasmuch as each of the pivot rings is capable of being shifted independently of the other, it follows that both sides of the pump assembly may function independently of one another, whereby the direction of how in each half of the pump assembly may be different, as well as the pressures developed.

Inasmuch as the port plate by its very construction, permits both sides thereof to be exposed to the liquid in the pump, regardless of the pressure conditions, such plate will be hydraulically balanced and being free to fioat axially within the space alloted to it, very little friction and very little hydraulic drag can develop between this port plate and the rotating porting rotor 61 or balance plate 115 which are rotating relative thereto.

For the pump assembly to function efiiciently, the pump vanes 47 must be exposed to an outward thrust to maintain the same in contact with the inner bearing ring 55 of the bearing assembly surrounding each of the rotors. This we accomplish hydraulically by continually exposing the inner edges of the vanes to liquid at the prevailing discharge pressure of the associated pump section in which the vanes are located.

Toward this end, each porting rotor 61 is provided with a circular groove 141 in that end facing the adjacent pump rotor, the diameter of the groove being such as to place the groove in line with the inner ends of the radial slots 41 in which the rotor vanes are slidably disposed. EX- tending longitudinally through each portiong rotor at and flow connecting the space 144 about the associated end spacer 111 with the circular groove 141 are preferably a plurality of passages 145.

To assure liquid in this space about each end spacer 111 at all times during pump operation, and at the discharge pressure of the pump, so that the vanes will be exposed to a corresponding pressure forcing them outwardly, a radial passage 147 is drilled through the port plate at a point between the diametrically opposed arcuate recesses 103 in such plate, and a cross-passage 149 is provided intersecting this radial passage and terminating at each end in flow connection with one of the radial passages 167. This cross-passage 149 is formed with an intermediate section of enlarged diameter providing a valve chamber with a valve seat 151 at each end thereof.

In this valve chamber is disposed a ball valve 153 adapted to shuttle from one valve seat to the other, depending upon the direction of pressure applied thereto. Thus, regardless of which of the arcuate recesses 103 happens to be carrying the high pressure how of the pump, the prevailing low pressure side will be closed off by the ball valve 153 while the high pressure fluid will find access through the radial passage 147 to the space 144 about the end spacer 111, from where the liquid may flow through the porting rotor passages 145 and into the vane slots behind the innermost edges of the vanes. Consequently, during operation of the pump assembly, all of the vanes will be maintained under continual hydraulic pressure driving them outwardly into pressure contact against the innermost race 55 of the surrounding bearing assembly 51 of the associated rotor assembly 31. With the vanes thus maintained in constant pressure against the inner race 55 of the surrounding bearing assembly 31, and with the inner race adapted to rotate freely with the included rotor assembly, it follows that a substantially leak tight fit may be maintained between the rotor assembly vanes 47 and the surrounding surface with essentially no frictional losses at the points of engagement.

Not only are such frictional losses essentially eliminated, but the bending stresses normally associated with frictional drag, which would normally occur in a conventional construction where the vanes slide along a surrounding fixed surface, are also substantially reduced. All of which enable the pump assembly to function at materially higher pressures, with less losses, reduced stress and strains, and consequently with greater efficiency.

The adjustment of each of the pivot rings may be accomplished manually, but we prefer to provide for hydraulic control of such adjustment whereby the adjustment may be controlled automatically if desired, whereby such adjustment can be made to respond to changing conditions in an associated hydraulic system.

Toward this end, we provide two pairs of opposing cylinder bores 161 in the flange 23 surrounding the opening in the pump housing 1, with each pair of opposing cylinder bores in line with the protruding stem 21 of one 0f the pivot rings. In each of these cylinder bores is slidably disposed a hollow piston 163 having a closed end extension 165 adapted to engage the protruding stem. An O-ring groove 167 about each piston is adapted to receive an O-ring 169 to slidably seal the piston in its cylinder bore.

Retention of the piston in its cylinder bore is effected by a cover plate 171 adapted to span adjacent cylinder bores, such plate being bolted to the flange 23 and provided with a threaded opening 173 to each cylinder for a pipe connection 175.

A spring 177 behind each piston functions to maintain a light contact between its piston and the stem 21 when hydraulic pressures are removed.

A cover plate 181 may be applied over the opening to the pump chambers as a protection to the pump assembly.

As liquid under pressure enters one of the cylinders, it will serve to eifect an adjustment of the associated pivot ring 15 and a corresponding adjustment of the associated pump. A flow of liquid to the opposing control cylinder will effect an adjustment of the associated pump in the opposite sense. By such means, either of the pumps involved in the twin pump arrangement illustrated and described may be adjusted independently of the other from a condition of maximum volume in the one direction through zero or neutral to maximum volume in the reverse direction.

Drainage of liquid from the housing chambers 11, 13 and associated spaces within the pump assembly is provided for by a pipe connection 185 leading from one or both of these chambers.

In lieu of the bearing assembly 51 between the rotor assembly 31 and pivot ring 15, we can provide a bearing ring 191 preferably of bearing metal such as brass or bronze, which ring is hydraulically balanced by applying pump pressure about the outer surface thereof which will substantially balance the pressure prevailing at any time against the inner surface of the ring, thus, in effect floating the ring in oil or such other liquid being pumped.

Toward this end, and with reference to FIGS. 7, 8 and '9 of the drawings, a pivot ring 193 similar to the pivot ring 15 of the first embodiment, but differing in the inclusion of a fitted bearing ring 194 of brass, bronze or like bearing metal, which ring is provided with diametrically located grooves 195 in the inner peripheral surface, separated by short lands 197. Concentric with this grooved ring 194 is a rotor ring 198 which the vanes 47 contact. Holes 199 through the ring 198, place the grooves 195 in communication with the proximate rotor chambers, whereby the pressures along the inner surface of the rotor ring will be substantially balanced by pressures created at corresponding points along the outer surface of this ring. The rotor ring thus is free to rotate, with the liquid as a lubricant, in response to the rotational movement of the rotor vanes, whereby rotor friction is reduced to a minimum.

Utilizing a somewhat similar principle, the bearing assembly 69 about each porting rotor 61, in the first embodiment, may be replaced by a bearing ring 205 of suitable bearing metal such as brass or bronze, the ring being preferably press fitted into position in its associated end housing 81. On the inner side of the bearing ring are diametrically located grooves 269 like those 195 in the gialring ring 194, and similarly separated by short lands Each of these grooves 2119 is placed in pressure communication with that intake-discharge port 95 farthest removed therefrom, in the embodiment as illustrated, by appropriate passages 215 through the end housing and bearing ring and coupled by suitable pipe connections 217.

With this arrangement, not only will the bearing ring 205 be maintained adequately lubricated, but what is of great importance in a pump of this type, the unbalanced pressures normally developed in a vane type rotor, which may be of the order of several thousand pounds, will be "(7 largely balanced by the application of the discharge pressure of the pump assembly to the diametrically opposite side of each of the porting rotors, thus relieving the bearing surfaces throughout the pump, of high unbalanced radial pressures to which they would otherwise be exposed.

Such balancing pressures will vary in accordance with pressures developed in the rotors, and with reversal of liquid flow through a rotor assembly, a corresponding shift of the compensating pressure will take place at the associated bearing ring 295, for the intake-discharge port which previously functioned as an intake port will now function as the discharge port and build up a balancing pressure in the opposite groove of the associated bearing ring 205. Accordingly, the unbalanced pressures characteristic of a positive displacement type pump will always be substantially balanccd, regardless of the magnitude or direction of such pressures.

It will be apparent from the foregoing, that our invention fulfills all the objects thereof, and while we have illustrated and described the same in considerable detail, the invention is subject to further alteration and modification without departing from the underlying principles thereof, and the same, furthermore, is not restricted to a twin pump but may be embodied in a single pump struc ture.

Accordin ly, we do not desire to be limited in our protection to the details as illustrated and described except as may be necessitated by the appended claims.

We claim:

1. A reversible, variable, positive displacement pump comprising a housing having a cylindrical chamber and an opening therefrom through the wall of said housing; a pivot ring of smaller outside diameter than said housing chamber and having a pump chamber defined in part by a cylindrical internal wall, a pivot pin opening outside said pump chamber opposite said housing opening, and a stem of smaller cross-section than said housing opening, extending from said pivot ring and into said housing opening; means pivotally securing said pivot ring in said housing with said ring adapted to swing through a neutral position of coinciding diameters; a shaft through said housing axially of said cylindrical housing chamber; a rotor on said shaft within said pump chamber, said rotor comprising a narrow cylinder having substantially radial vane slots in the periphery of said cylinder, intake-discharge fiow channels terminating in the periphery of said cylinder between said vane slots, and a vane slidably positioned in each of said vane slots; slidable bearing means interposed between said pivot ring and said rotor with the outermost edge of each vane adapted to engage said hearing means to form peripheral chambers about said rotor; means providing for flow of liquid to and from said rotor, said means comprising a porting rotor keyed to said shaft with one end in effective engagement with said rotor, said porting rotor having a plurality of radial ports adjacent 'its other end and corresponding in number to the pump rotor intake-discharge channels, a longitudinal passage connecting each of said radial ports with one of said intake-discharge channels of said rotor; an end housing encircling said porting rotor and aflixed to an end of said pump housing, said end housing having a pair of diametrically located radial openings opening to said porting rotor and in substantially the plane of said radial ports, whereby, upon rotation of said porting rotor, each of said radial ports will alternately align itself with each of said radial openings in said end housing, to alternately take in liquid through one of said radial openings at low pressure and discharge the same through the other of said radial openings at higher pressure; means for driving said pump; and means for selectively adjusting said pump rotor about said pivot from a position of maximum capacity of flow of said pump in one direction, through said neutral position of coinciding diameters, to a position of maximum capacity flow of said pump in the reverse direction.

2. A reversible, variable, positive displacement pump comprising a housing having a cylindrical chamber and an opening therefrom through the wall of said housing; a pivot ring of smaller outside diameter than said housing chamber and having a pump chamber defined in part by a cylindrical internal wall, a pivot pin opening outside said pump chamber opposite said housing opening, and a stem of smaller cross-section than said housing opening, extending from said pivot ring and into said housing opening; means pivotally securing said pivot ring in said housing with said ring adapted to swing through a neutral position of coinciding diameters; a shaft through said housing axially of said cylindrical housing chamber; a rotor on said shaft within said pump chamber, said rotor comprising a narrow cylinder having substantially radial vane slots in the periphery of said cylinder, intake-discharge flow channels terminating in the periphery of said cylinder between said vane slots, and a vane slidably positioned in each of said vane slots; slidable bearing means interposed between said pivot ring and said rotor with the outermost edge of each vane adapted to engage said bearing means to form peripheral chambers about said rotor, means providing for flow of liquid to and from said rotor, said means comprising a portingvrotor keyed to said shaft with one end in effective engagement with said rotor, said porting rotor having a plurality of radial ports adjacent its other end and corresponding in number to the pump rotor intake-discharge channels, a longitudinal passage connecting each of said radial ports with one of said intake discharge channels of said rotor; an end housing encircling said porting rotor and affixed to an end of said pump housing, said end housing having a pair of diametrically located radial openings opening to said porting rotor and in substantially the plane of said radial ports, whereby, upon rotation of said porting rotor, each of said radial ports will alternately align itself with each of said radial openings in said end housing, to alternately take in liquid through one of said radial openings at low pressure and discharge the same through the other of said radial openings at higher pressure; means for driving said pump; and means for selectively adjusting said pivot ring about said pivot from a position of maximum capacity of flow of said pump in one direction, through said neutral position of coinciding diameters, to a position of maximum capacity flow of said pump in the reverse direction; said means including a cylinder to each side of said stem in spaced relationship thereto, a piston in each of said cylinders and a push rod extending from said piston into contact with said stem, each of said cylinders having a liquid flow connection thereto behind the piston therein.

3. In a pump assembly of the positive displacement type involving a shaft, and a rotatable assembly on said shaft including a rotor assembly wherein the radial pres sures developed are unbalanced and predominantly to one side of the shaft, means for reversing direction of liquid flow through said pump assembly with accompanying reversal of the location of said radial pressures about said shaft, a pair of intake-discharge ports, means for substantially balancing said radial pressures about said shaft regardless of the location of said radial pressures, said means including a bearing ring to each side of said rotor assembly and surrounding said shaft, each of said bearing rings having a pair of similarly disposed grooves in the inner side thereof at diametrically located positions, means providing a liquid pressure connection from one of said intake-discharge ports, when functioning as a discharge port, to those corresponding grooves in said bearing rings which develop balancing hydraulic pressures under prevailing operating conditions, and similar means providing a liquid pressure connection from the remaining intake discharge port to the remaining groove in each of said bearing rings when said remaining intake-discharge port is functioning as a discharge port.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Westinghouse Nov. 26, 1895 Hawkins July 3, 1923 5 Streckert Oct. 28, 1930 Ott Aug. 18, 1931 Ott Jan. 15, 1935 Lane Ian. 3, 1939 Wilson et a1 Jan. 26, 1943 10 Wahlmark Nov. 10, 1953 Dolza et a1. May 22, 1956 10 Miller et a1 Oct. 2, 1956 Wagner Feb. 4, 1958 Deschamps May 12, 1959 Woodcock Dec. 29, 1959 Gau'oatz Oct. 11,1960 Menon Jan. 24, 1961 FOREIGN PATENTS Great Britain of 1915 France Sept. 19, 1938 Italy June 20, 1956 

1. A REVERSIBLE, VARIABLE, POSITIVE DISPLACEMENT PUMP COMPRISING A HOUSING HAVING A CYLINDRICAL CHAMBER AND AN OPENING THEREFROM THROUGH THE WALL OF SAID HOUSING; A PIVOT RING OF SMALLER OUTSIDE DIAMETER THAN SAID HOUSING CHAMBER AND HAVING A PUMP CHAMBER DEFINED IN PART BY A CYLINDRICAL INTERNAL WALL, A PIVOT PIN OPENING OUTSIDE SAID PUMP CHAMBER OPPOSITE SAID HOUSING OPENING, AND A STEM OF SMALLER CROSS-SECTION THAN SAID HOUSING OPENING, EXTENDING FROM SAID PIVOT RING AND INTO SAID HOUSING OPENING; MEANS PIVOTALLY SECURING SAID PIVOT RING IN SAID HOUSING WITH SAID RING ADAPTED TO SWING THROUGH A NEUTRAL POSITION OF COINCIDING DIAMETERS; A SHAFT THROUGH SAID HOUSING AXIALLY OF SAID CYLINDRICAL HOUSING CHAMBER; A ROTOR ON SAID SHAFT WITHIN SAID PUMP CHAMBER, SAID ROTOR COMPRISING A NARROW CYLINDER HAVING SUBSTANTIALLY RADIAL VANE SLOTS IN THE PERIPHERY OF SAID CYLINDER, INTAKE-DISCHARGE FLOW CHANNELS TERMINATING IN THE PERIPHERY OF SAID CYLINDER BETWEEN SAID VANE SLOTS, AND A VANE SLIDABLY POSITIONED IN EACH OF SAID VANE SLOTS; SLIDABLE BEARING MEANS INTERPOSED BETWEEN SAID PIVOT RING AND SAID ROTOR WITH THE OUTERMOST EDGE OF EACH VANE ADAPTED TO ENGAGE SAID BEARING MEANS TO FORM PERIPHERAL CHAMBERS ABOUT SAID ROTOR; MEANS PROVIDING FOR FLOW OF LIQUID TO AND FROM SAID ROTOR, SAID MEANS COMPRISING A PORTING ROTOR KEYED TO SAID SHAFT WITH ONE END IN EFFECTIVE ENGAGEMENT WITH SAID ROTOR, SAID PORTING ROTOR HAVING A PLURALITY OF RADIAL PORTS ADJACENT 